Sankaracarya's Vivekachudamani 571

आवृतेः सदसत्त्वाभ्यां वक्तव्ये बन्धमोक्षणे ।

नावृतिर्ब्रह्मणः काचिदन्याभावादनावृतम्

यद्यस्त्यद्वैतहानिः स्याद्द्वैतं नो सहते श्रुतिः ॥

āvṛteḥ sadasattvābhyāṃ vaktavye bandhamokṣaṇe |

nāvṛtirbrahmaṇaḥ kācidanyābhāvādanāvṛtam

yadyastyadvaitahāniḥ syāddvaitaṃ no sahate śrutiḥ ||

(Sankaracarya's Vivekachudamani 571)

When there is the presence or absence of veiling, bondage and liberation can be spoken of. There can be no veiling for Brahman as It is obvious, there is no second thing besides it. If there is, it will contradict the non-duality of Brahman; the scriptures will never allow duality.

This sloka is very important, Sankaracarya is explaining when the Supreme Lord is present or when people do not see him there may be many religions that can be claiming the Lord belongs to them. Even one is attached to material or Maya, even one is in the state of completely understands the Lord. There is no way one can divide the Lord according to their status. There is no second the entire creation be without him. If someone says otherwise it will against the one and only Supreme Lord Kesava. The Vedic literature never mentioned there are various Gods. There is only one and only Supreme Personality of Godhead Sri Ramachandra.

In this text the Lord is mentioned as Brahman but in Bhagavad Gita Lord Krishna clearly claiming that he is the Paramatma, Brahman, and Bhagavan.